Case report
A 44-year-old man with a history of occasional melena since childhood presented to our hospital with a complaint of acute lower GI bleeding. The physical examination showed no abnormal findings. Laboratory evaluation revealed decreased hemoglobin (10.4 mg/dl). The patient underwent esophagogastroduodenoscopy and total colonoscopy. Although bright red blood was seen with colonoscopy, the source of bleeding was not identified (Figure 1a, 1b). Furthermore, the source of bleeding was not found with abdominal contrast-enhanced computed tomography (CT). The patient was diagnosed with OGIB, and CE was performed subsequently to examine the small intestine. Normal intestinal fluid was shown by CE, and it was difficult to identify the source of bleeding (Figure 2a, 2b). We explained the necessity of performing BAE to the patient, however he did not consent to BAE at that time. Fortunately, the bleeding stopped spontaneously. Magnetic resonance imaging in the outpatient department at follow-up did not identify the source of bleeding. The patient was prescribed with Rebamipide at the time of follow-up. After 9 months, the patient presented to our hospital again with lower GI bleeding. Since detailed testing including CE had already been performed with the previous bleeding, BAE was the first test performed after obtaining informed consent. A diverticulum was revealed by BAEĀ in the ileum at the 50cm oral side from the ileocecal valve, and intestinal stricture was observed near the diverticulum (Figure 3a). It was difficult to traverse the colonoscope, and the small bowel series with Gastrografin showed the blind end that corresponds to the diverticulum and the stricture (Figure 3b). Although no active bleeding was observed during the BAE procedure, there were no other possible sources of bleeding. Therefore, we diagnosed MD as the source of bleeding, and decided to treat the patient surgically. The diverticulum was apparent, and segmental small bowel resection with primary anastomosis was performed (Figure 4a,4b). Pathology of the surgical specimen showed the true diverticulum with a small erosion (Figure 4c), and heterotopic gastric mucosa was seen in the diverticulum; therefore, MD was diagnosed pathologically (Figure 4d). The patient has had no lower GI bleeding since surgery.